2017 Volume 71 Issue 1 Pages 361-366
The properties of concrete surface which influence the durability of concrete structure will be affected greatly on curing conditions. Therefore, the general environment, in case of using the normal portland cement, the wet curing has to carry out for 5 days. The occasion using the poretland-blast furnace slag cement typeB, the wet curing has to carry out for 7 days. However, the influence of durability that drying concrete surface before preparation of wet curing isn’t obvious. In this study, the effects of demolding timing and the wet curing timing on air permeability, surface hardness and strength of concrete with normal portland cement and poretland-blast furnace slag cement typeB were investigated. As a result, the following two became clear.
（1）If the demolding timing became early, the quality of concrete surface became badly. The one of the concrete with poretland-blast furnace slag cement typeB was more influential than the concrete with normal portland cement. However, the wet curing was performed even if mold was removed early, the surface quality of concrete could be improved.
（2）The coefficient of air permeability and the rebound number didn’t undergo by the influence of drying concrete surface before preparation of the wet curing. However, the compressive strength of cover concrete was small, when the wet curing starting became late after demolding. And the influence of lower concrete strength, the concrete with poretland-blast furnace slag cement typeB was larger than the concrete with normal portland cement.
